1. Field of the Invention
This invention relates solid state lasers, and more particularly to multi-faceted reflectors for use in pumping slab geometry solid state lasers.
2. Description of the Prior Art
As a solid state laser medium there are known such media as a slab solid state laser medium (FIG. 1) and a rod geometry solid state laser medium (FIG. 2)
The slab geometry solid state laser medium is face pumped. The laser beam excited in the medium is reflected between the top and bottom surfaces, propagates the whole length of the medium, and is emitted from the end face. Therefore, the beam is free from thermally induced optical distortion along the thickness of the medium. Also an output beam emitted from the end surfaces of the slab has an improved quality over a rod geometry solid state laser.
The performance of the slab geometry solid state laser is, however, highly sensitive to the flashlamp pumping illumination distribution. In other words, the flashlamp intensity distribution directly affects the gain profile as well as the thermal energy distribution in the crystal volume. Therefore, reflector design must be carefully considered if the laser is to perform with a minimum of optical distortion. Nevertheless, the conventional reflector is made of a monolithic specular surface so that it is difficult to adjust optimally the illumination density to the laser medium in response to the form of the laser medium and other factors. Therefore, the problem exists that it is difficult to output a laser light with optimal profile.